EDIT - as with all aluminum bolts in the engine block, you should just go ahead and replace them, even though I did not replace mine in the DIY. I list the part numbers below for my 2007 e90 335i.

EDIT - Removing the engine cowl (cabin filter housing) makes this job easier. I do not have a DIY for that, but once you remove the wiring harnesses from the cowl (steps 7 and 8), it's pretty easy to remove the cowl - several 10mm screws. Removing this will make several steps, including the engine cover (step 15a), WAY easier.

I wonder how many people (like me) got the call from the service department to tell them that all three needed to be done (at a cost of over $1500). Maybe because the three problems are related? Little hardened bits of rubber from the OFH gasket circulate throughout the cooling system and eventually foul the water pump and thermostat. At least that's my theory. I know that I found lots of black rubber bits in my coolant when I replaced the water pump/thermo.

There is a great DIY for this procedure on the N52 engine at http://www.e90post.com/forums/showthread.php?t=476419. However the process is a piece of cake on the N52 - not so lucky on the N54. I swiped this photo (posted by user allmotor22) to show the general location of the three Oil Filter Housing (OFH) bolts on the N54. It's the #1 bolt that causes all the problems because it's completely under the intake manifold.

This DIY is intended to document my own DIY procedure for a 2007 e90 335i with automatic trans. and no sport package. Use this procedure at your own risk. Your results my vary, based on options. For example, your OFH may have an oil cooler attached, and you may have a 6MT that requires unbolting the intercooler to drain the coolant. See comments below from member NukeZero - he provides insights into the differences on the 6MT with oil cooler.

PLEASE if you see anything amiss here let me know and I'll update the DIY. In some cases I took the photos after-the-fact so things may seem out-of-step (for example, in step 2 you drain oil and remove filter, and in step 5 you remove the air intake duct - but the photo for step 5 shows the filter cap still on).

On one DIY the poster used blue tape (like painter's tape) to tape up anything that needed to get reattached - good advice since I woke up in the middle of the night realizing I'd missed step 38.

This job took me about 6 hours, but I'm a noob. Others have claimed much shorter time-frames.

Parts:
- Oil Filter Housing (OFH) gasket part#11427537293
- Oil filter kit part#11427566327
- OFH Bolts part# 11427540759, 11427540763, 11427540758
- Gallon of BMW antifreeze part#11141467704
- 7 quarts of BMW oil part#11510017866
- You may want a new set of air intake manifold gaskets part#11617547242
- You may want to replace the air filter element since you'll have it out anyway part#13717556961
- Review step 20a: removing the coolant hose from the engine block to gain additional clearance for a larger wrench on OFH bolt #2. If you do this step, you should replace the o-ring; part#11537545278

Tools:
8mm nut driver to remove the splash guard
3/8 drive metric socket set with 5-6" extension
1/4 drive metric socket set with 6"extension
1/2 drive 17mm socket and ratchet (to remove oil drain plug - 3/8 will do in a pinch)
1/4, 3/8 and 1/2 torque drivers for the above socket sets if you have them
Stubby flathead screwdriver
Regular flathead screwdriver
Awl or pick
Magnetic extension pick-up tool (if possible get the kind that has the side-protector sleeve that keeps it from being attacted to everything but what you're after)
3/16 allen wrench
T20 torx nut driver
Oil filter strap wrench
Oil and coolant catch pans
Funnel (with a filter screen if you're saving your coolant)
Extensible mirror (optional - you may need this just to see what you're doing in the aft part of the manifold, or to extract something you dropped)
Medicine (not medical) syringe (optional - for extracting oil)
Lots of rags
Nitrile gloves

Steps:

1. Disconnect the battery - look for a battery DIY. Why you ask? Probably always a good idea, but there is an unprotected positive battery connection directly below the next-to-last aft nut on the intake manifold - believe it goes to the starter? If you drop a socket extension down there you will quickly see that it is live.

2. Drain oil and remove filter. See oil change DIY - http://www.e90post.com/forums/showth...t=4768&page=16. This involves jacking or ramping car and removing the splashguard. I know it's possible to change the oil without jacking/removing the splashguard, but you'll need to remove the splashguard for the next step anyway (draining coolant), and it's necessary to jack/ramp to get the splashguard out. Also, once you drop the splashguard you will see very quickly that it needs lots of clean-up. (your bad gasket leaked lots of oil - where do you think it all went?)

3. Remove the excess oil puddled in the bottom of the OFH. A simple medicine (not medical) syringe works nicely to remove oil left in bottom of filter housing. Otherwise just use rags. When done stuff a clean rag into the main OFH body to prevent any bits from getting in there.

4. If not replacing water-pump/thermostat at the same time, drain several quarts of coolant (see partial coolant flush DIY http://www.e90post.com/forums/showthread.php?t=551742). The OFH has a coolant hose attached (coolant runs through the unit) and you don't want to release all that coolant onto your alternator and engine when you remove the hose/OFH. Save the coolant if you want for reinstall later, but I recommend filtering it if you do.

5. Remove front intake duct using a T20 torx on the two screws. The intake duct attaches to the air filter housing with two small tabs (one on each side) that can be easily pried loose by hand or with a screwdriver.

6. Pop the 5 spring clips on top of the air filter housing, lift the cover off and remove the air filter element.

7. Release the first (fore) vacuum/wiring harnesses on the windshield wiper sill to gain a little more clearance. This may not be necessary but it gives you some more clearance. Lift cover off by prying the four clips along the front, then use the awl to depress the small tab on each of three retaining clips in the rear and slide unit forward and off the rails.

8. Release the second (aft) wiring harness. This may not be necessary but it gives you some more clearance. Use the awl to depress the small tab on each of three retaining clips and slide the unit forward and off the rails.

9. Disengage whatever this is (sorry, not sure what it is) by depressing the sides of the fitting and lifing up - plug the hole with cloth or cover with tape.

10. Remove front air hose from air filter housing by loosening clamp with a screwdriver and sliding hose off.

11. Remove the rear (aft, cabin) air hose from air filter housing by using a stubby screwdriver to loosen clamp and then slide hose off.

12. Each of the vacuum/wire harness lines from steps 7 and 8 are clipped to the side of the air filter housing on the driver's side. Disengage by simply pulling each of the three rubberized clips up.

13. The air filter housing is ready to come out. It is held in with three rubberized grommets fitted over plastic posts on the intake manifold - one fore and two aft. Pop the forward one by grasping the air filter housing firmly and wiggling it back and forth while pulling up. Same with the aft-right. For the aft-left, you will need to slide a pry bar underneath and pry it up. Pull the air filter housing out.

14. Remove the electrical connector and the coolant hose from the OFH. (Note that metal clips on HOSES are pried up, but metal clips on ELECTRICAL CONNECTORS are pushed in) Pry up the metal clip on the hose until it stops, then work the hose off the OFH. Push the clip in on the electrical connector and pull the connector off the OFH.

15a. Remove the engine cover to gain a little clearance for the two aft manifold nuts. This may not be necessary but it's a fairly easy step and it did seem to help. The cover is held on with four 3/16 allen bolts, two fore and two aft - one aft bolt is on the left (passenger) side of the cover and the other aft bolt is on the top of the cover. The aft one on the top of the cover is in a very tight space, so patience is needed to work it out with an allen wrench. I used an allen wrench to break it, and once it was loose I used an allen bit to finish the removal by hand, but it was very tight. The magnetic pick-up tool is useful for extracting the bolt once it's loose. Remove the two fore bolts.

15b. Before pulling the engine cover off remove the oil filler cover. Do this by opening the cover as usual (1/2 turn counter-clockwise and flip open), and then with the lid flipped open turn the entire unit (cover and base) clockwise about 1/3 turn until it releases. With the oil-filler cover off, ease the engine cover out.

16. Release the charge pipe from the throttle body by popping the metal clip up and working the pipe loose. Do not remove the metal clip - just pop it up until it stops. This step may be unnessecary if you are not fully removing the manifold, but it gives you more room to wiggle the manifold loose.

17. Remove air intake manifold. This part seemed scary to me (noob), but it has to come out in order to gain access/clearance for that infamous first bolt on the oil filter housing. The manifold is held on with one bolt (fore) and six nuts (one between each of the 5 manifold outlets, and one aft). Working from the front of the car back, the nuts are staggered - low, high, low, high, low, high. Remove the fore manfold bolt and the first 4 nuts - these are easy. The two aft nuts are not visible and you'll have to get them out with a short (~5") extension. Once you break them (they shouldn't be very tight), work them off by hand with just the extension/socket. BE CAREFUL not to drop the nuts down in the engine bay! I worked them by hand with the socket extension to nearly-off, then used my hands to work them loose the rest of the way. Fortunately the bolt pins have a nipple on the top so the nut stays on even after it's completely loose Once loose I used the magnetic extension to extract them.

18. Make sure there is no debris on top of the manifold (blow it off with compressed air if you've got it), then pull the manifold up and loose. I did not remove it completely - just enough to make sure I had sufficient clearance for that first OFH bolt. CAUTION: I recommend pulling the intake all the way out for inspection - in the very least check the gaskets and make sure they are properly aligned. Some people like to replace the gaskets, others have said they've had the manifold off numerous times without replacing the gaskets. Obviously I elected to NOT replace the gaskets since I never fully removed the manifold. One more thing to keep me awake at night. If you do pull the manifold always plug or cover engine openings until you're ready to reassemble, and then make sure to remove your plugs/coverings. But if you're like me and leave the manifold on, you may need to wedge a screwdriver handle or something between the manifold and the oil filter housing to get it to stay out of the way.

19. There are two small wiring harnesses running between the manifold and the first bolt on the oil filter housing. These wires may interfere with your attempt to access that bolt, so I moved them by popping the small connecting clip off the manifold and moving the wires out of the way in order to gain direct and unobstructed access to that first bolt.

20a. Once you have moved the manifold sufficiently and moved those wires out of the way you will have direct access to the first oil filter housing bolt. I found that a 1/4 drive ratchet with a 6" extension and an 8mm 6-point socket worked for that first bolt. USE A TORX BIT if at all possible - you don't want to strip one of these: see comments below. I used a metal pipe to gain some leverage and the bolt broke easily. Next remove the number three (top) bolt. At this point I marked the top bolt just to avoid any confusion later, although it would be pretty difficult to get the three bolts (all different sizes) mixed up. I actually found the number two (bottom, shortest) bolt to be the most difficult to break. It appears readily accessible, but the space is tight because of the coolant hose right beneath it. One caution - the wimpy 8mm heads on these bolts will STRIP EASILY. The (small) 8mm flex ratcheting box-end wrench I have is perfect for this job, but it just felt as though either the bolt head was going to strip or the delicate wrench was going to break. I decided to move the engine block coolant hose by removing the two 10mm bolts that attach the coolant hose coupling to the block (see photo below). The hose has a sealing o-ring so it takes a little wiggling and a gentle pry on the hose flange with a screwdriver to pop the hose out of its fitting. If you remove this hose, it's a good idea to replace the O-Ring (see part# at top of this post).

20b. With this hose out of the way I had all the clearance I needed to put a beefier 3/8 drive 8mm socket on the last OFH bolt. AGAIN - USE A TORX SOCKET IF YOU CAN - you don't want to strip this bolt head: see comments below. I used a pipe for leverage just to eliminate any doubt (picture below), and the bolt broke easily. Just make sure you hold the socket tight on the bolt with one hand while ratcheting/leveraging with the other so as not to slip and strip the bolt head. With all three bolts removed, pop the OFH off the engine block and set it aside for cleaning.

21. Clean the block. You will notice some black rubber residue from the old gasket on the engine block. Clean the block with a soft cloth and some brake cleaning fluid. I did not want to spray directly into the engine bay so I sprayed the fluid onto the cloth and used some elbow grease to completely clean the block.

22. Remove the old gasket from the OFH - use an awl (careful not to scratch the OFH) to get it started and it should just pull right out. Clean things up generally and put the new gasket on. Once I had the gasket in I applied a VERY SLIGHT coating of oil to it - not sure if this is proper or not.

You are now ready to begin putting it all back together.....

23. Reinstall the OFH. Keep that clean rag stuffed into the main OFH body to prevent any bits from getting in there. Snug the three bolts and then tighten in a rotating pattern - first one, then the next, then the next - 1/4 turn at a time until tight. Tighten to 22nm if you have a torque wrench, otherwise tighten until the bolts stop, and not further.

24. If you removed the coolant hose from the engine block in Step 20a, reattach it now. Replace the O-Ring - I reused my old one and it worked, but at $8 it's best to replace this part. It is surprisingly difficult to get the two 10mm bolts threaded. Be patient. I inserted the bolts into the hose flange and got them threaded into the block BEFORE seating the hose into the housing. Make sure you seat the hose though, before tightening the bolts snug - otherwise you risk breaking the hose flange. Once snug, I just torqued in an alternating pattern until tight.

25a. Reattach the manifold to the head. This step is much easier than pictured here, if you removed your engine cowl. The writeup for steps 25a and 25b here is based on not having removed the engine cowl. The fore bolt and first 4 nuts are easy - get them started and hand-tightened. The high bolt stems are easy to get the nut started. The low ones are difficult to reach with your fingers to get the nut started. A magnetic extension on your ratchet would do the trick nicely, but I didn't have one. I used the magnetic extension pickup-rod to get the nut into place, then slid the rod off - the bolt stems have nipples at the top that will hold the nut on the stem while you slide the magnetic pick-up off. Once I had the nut on the stem, I started them by hand and then used a ratchet extension with an 11mm socket (I think it's 11mm) to hand-tighten.

(note that in the following pictures I demonstrate the concept on one of the high bolt stems, but the technique is only necessary for the low bolt stems)

25b. The last nut is the easier of the two aft nuts. You can actually see the bolt stem since it's a high one. I got that one started with my fingers. The next-to-last one is trouble. You can't see it since it's a low one. You can feel the bolt stem, but you can't fit two sets of fingers down in there to guide the nut onto the stem. And I didn't feel confident enough to hold the nut between two fingers to try and find the stem and get it started (you will see that dropping the nut is trouble). I actually did drop the nut and was lucky enough to be able to see it and extract it with a magnetic pick-up. I also dropped a ratchet extension with socket down there when the extension slipped off the ratchet. A word of caution: make sure your ratchet holds the extension tight - try to pull it off and if it slips right off with no resistance I recommend investing in another ratchet or extension (whichever is the problem). I got the nut onto the stem using the magnetic pick-up trick, and then hand-tightened with an extension and socket. Using the magnetic pickup allows you to use your other hand to feel it onto the bolt stem - otherwise a mirror will help.

With all nuts (and one bolt) hand-tightened, begin torqueing down evenly across all bolts - that is, tighten one bolt 1/4 turn, then the next, and next, and so on, and then start all over again. Do this until the nuts (and one bolt) are very snug - do not overtighten. You will recall that when you loosened the nuts to remove the manifold they were not very tight and therefore easy to loosen. Keep that in mind.

26. Reinstall the charge pipe to the throttle body - wiggle it onto the throttle body until snug and then push the clip into the locking position. Test to make sure it's tight and won't come off.

27. Attach the electrical connector to the OFH - push until it clicks and test that it won't come off.

28. Attach the small wire harness from step 19 back to the air intake manifold by reinserting the nipple into the hole in the manifold from underneath.

29. Reinstall the engine cover. Strangely, this was the most difficult step for me. After getting the cover into position, check all the way around that nothing is pinched - wires, vacuum hoses or even that insulation on the underside of the cover (it is likely loose and may protrude once you get the cover in position). The aft allen bolt is a bugger to get started. I finally got it to work by installing the front two allen bolts first (but not tightening them completely). This seemed to get things sufficiently aligned to get that back bolt started properly. I then used the allen wrench to finish it up - but it took patience.

30. Reinstall the oil fill cap by reversing step 15b.

31. Reinstall the OFH coolant hose. This style hose is keyed - there is a slot at the top, right where the clip lifts up. That slot aligns with the tab on the OFH receptacle. Push it in tight and then push the clip down into position. Test it to make sure the hose won't pull out.

32. Put the air filter housing into place - work it in underneath those wiring harnesses so that the three rubber grommets align with the posts on the manifold - but don't push them into locking position yet.

33. Reattach the after (cabin) air hose at the back of the housing. Space is tight and you'll have to wiggle it snug. Use your stubby screw driver to tighten the clamp.

34. Double check that the rubber grommets on the housing are still aligned with the posts on the manifold and push down on the the air filter housing to lock it into place.

35. Reattach the forward air hose to the front of the air intake housing - push it in snug and tighten the clamp.

36. Reattach the aft wiring harness into the wiper sill by aligning the three slide tabs and pushing in until it clicks.

37. Reattach the fore wiring harness conduit into the wiper sill. IMPORTANT - insert the wiring harness and vacuum line into the bottom tray of the conduit FIRST. Then attach the bottom tray by aligning the three sliding tabs and pushing in until it clicks. Attach the conduit tray top.

38. Reattach the three wiring harness rubber clips to the side of the air filter housing.

39. Reinstall the air filter and install the filter housing top. Note that the top has three sets of tabs on the back that must align with (and go into) the three sets of holes in the back of the air filter housing. Press all five spring clips back up into locking position.

40. Reinstall the front intake duct.

41. Make sure the oil plug is put back in with the new crush washer (make sure you took the old one off and can account for it) and torqued to spec (25nm - see oil change DIY). Add 6 quarts of oil - pour ~half the sixth quart into the filter housing.

42. Replace the two o-rings on the filter cover and lightly oil them. Push the new filter sleeve into the cap, insert the cap/filter assembly into the OFH and torque the cap to 25nm (or very snug with a filter wrench).

43. If you are discarding your old coolant, mix the fresh BMW coolant 50/50 with distilled water. Remove the coolant reservoir cap and bleed screw. Pour your coolant mixture in until it appears that it will begin to come out of the bleed hole. Replace bleed screw and reservoir cap.

44. Reconnect the battery.

45. Follow these instructions to vent the coolant system (some people recommend attaching a battery charger, but your car battery should be able to handle 12 minutes with the headlamps on):
- Insert key in the dash
- With foot OFF the brake (don't want to start the car), push the start button (headlamps and interior systems come on).
- Turn both temp dials as high as they will go (84 degrees) and put the fan on the lowest setting.
- Push the accelerator pedal in for ten seconds then let go - you will hear the water pump cycle on. Then let it go.
- Check the time or set a timer for 12 minutes. In this time period you will hear the water pump cycle on and off and coolant gurgling at the reservoir.
- After 12 minutes turn the car off, remove the reservoir cap and check the fluid - it should be slightly below where you started.
- Repeat.

46. Start the car and keep your eye on the temp gauge. If it begins to climb turn the engine off immediately - something didn't work with your fill/bleed/vent process. Try it again.

47. Check the oil level (click the left-hand stalk programming thumb-button upward until the dash indicator says "Oil", then press the outer stalk button in. The system may take a minute or two to register the oil level. Depending on how much of your oil you drained earlier, you may need to crack that 7th quart and top it off. It should NOT take the full 7th quart (unless you somehow drained every single drop), but it may take half.

great write up. I actually used this over the weekend to replace my OFH gasket. Although I found out that my coolant was leaking from the coolant hose from step 20a, the one with 2 bolts attaching it to the head because the o-ring and its fitting were deteriorated.

One thing I do recommend to anyone planning to follow this. To make everything a lot easier(referring to the aft bolts on the manifold and engine cover), go ahead and remove the window sill cover(that the cabin air filter sits on). It takes a few minutes and gives you so much more room. To remove this, refer to any JB4 installation guide. If i remember correctly, it is only 6 screws/bolts for the cabin filter, and 2 for the window sill cover and then it pops right out.

FYI, you dont have to remove that coolant hose from the front of the engine. A small wrench fits in there just fine. I also removed the fan as it made alot more room and takes about 1 minute to pull out. The fan comes out with one screw on the left side, unplug and lift up. Super easy and much easier access.
Couldn't hurt to change that oring anyway, but without the fan in the way I'm sure its much easier.

FYI, you dont have to remove that coolant hose from the front of the engine. A small wrench fits in there just fine.

Agreed. As I mentioned in the DIY the issue I had was that the small wrench didn't feel as though it would break the bolt free without stripping it, so I moved the hose to gain additional clearance and get a more substantial wrench on it.

Thanks for the great write-up. I tried this last wknd and ended up stripping bolt #2 despite having a etorx box wrench. It just wouldn't break free. Any ideas how I should remove it now? It was frustrating to get all the way to that step and then have to put everything back together b/c of that bolt. I didn't remove the fan (but did remove the coolant hose), but space was still limited...couldn't get enough torque to it even w/an Irwin bolt out socket.

Thanks for the great write-up. I tried this last wknd and ended up stripping bolt #2 despite having a etorx box wrench. It just wouldn't break free. Any ideas how I should remove it now? It was frustrating to get all the way to that step and then have to put everything back together b/c of that bolt. I didn't remove the fan (but did remove the coolant hose), but space was still limited...couldn't get enough torque to it even w/an Irwin bolt out socket.

That must have been very frustrating indeed. Next time I'd start with that bolt and try vice grips if you can get them on. Otherwise, post in the general forum to see if you get advice there on how to extract a stripped etorx bolt. Post back here when you find your solution - it may help others.

Special thanks to edrive90 for his assistance. I like to add some instructions to performing this on a E92 335i with Sports package and 6MT.

You should remove the intercooler to get to the radiator drain plug. The intercooler is super easy to remove. Two T-20 or T-25 torx screw on each side. Then pull the quick-clamp from the charge pipes off. When the intercooler falls out, you will see a blue plastic screw on the driver's side. This screw is the radiator drain plug. Unscrew this to drain the radiator fluid.

1. Once you have remove the intake manifold or pushed it aside, there are 3 bolts to remove on the oil filter housing gasket. The bottom bolt is the worst as you MUST remove the coolant-to-radiator hose by removing those two bolts that hold the flange. Once this hose is removed, you have another problem. The stock oil cooler lines will be in the way and they are difficult to remove out.

2. You will need a long extension, 12-inches 1/4 drive and go in from the passenger side to break the last bolt on the oil filter housing. I did not remove the radiator fan since I was lazy. There is not much wiggle room to work with. If you get frustrated, I highly recommend now to remove the radiator fan.

2.b. To remove the radiator fan, there are 3 things that must be done. Very simple. On the passenger side at the top corner, remove that T-25 torx bolt. At the top of the radiator, unclip all electrical lines from the clips. At the driver's side, there is a big electrical connector. Un-plug that by squeezing it. At the driver's side, there is a plastic mechanism that latches the radiator fan. Just push this latch so it will release and allow you to glide out the radiator fan.

You will then notice the radiator fan is still held down by a rubber grommet to the outlet charge pipe. If you can't break it free, reach down and lubricate the grommet with synthetic grease like I did. Use a flat head screwdriver to push down on it so you can slide the radiator up. Don't worry, you won't break the grommet. It is quite tough. The grommet has a slit that is designed for a screw driver to slide into.

3. Once you have removed this bolt, remove the other oil filter housing bolts.

4. If you have the stock oil cooler, you will need to unscrew a bolt underneath the oil cooler lines. I believe it is a 12mm. The oil cooler flange will fall out of the oil cooler. At this point, you may see some oil drip.

5. The oil filter housing and oil cooler lines should be removed from the car now as 1-piece. You will need to separate it. There are 3 bolts holding the oil cooler thermostat housing unit to the oil filter housing. You should definitely replace the gasket that is in-between. The gasket part number is: 11427525335

6. Re-install the oil cooler lines into the oil filter housing unit. Bolt everything back up to 22Nm or 16.22 ft-lb.

7. Bolt the oil filter housing back up. Remember to also bolt the coolant hose from the engine block to the radiator back up as well. Again, replace that o-ring as well.

Special thanks to edrive90 for his assistance. I like to add some instructions to performing this on a E92 335i with Sports package and 6MT.

You should remove the intercooler to get to the radiator drain plug. The intercooler is super easy to remove. Two T-20 or T-25 torx screw on each side. Then pull the quick-clamp from the charge pipes off. When the intercooler falls out, you will see a blue plastic screw on the driver's side. This screw is the radiator drain plug. Unscrew this to drain the radiator fluid.

.

You dont have to completely remove the intercooler, just remove the torx bolts, that will give enough space to reach the drain without unhooking the charge pipes. A long screwdriver with a big head should be able to twist the plastic plug. I didnt have a big screwdriver, what i did is i stuck a penny upright at the en of a hex extention and thats how i unscrew the cap

OP, this is great! I just noticed the post and I had just replaced my two gaskets in my oil filter housing and oil cooler attachment a week before you posted this. I have a 6MT 335i and it was difficult but not bad. I was doing an intake valve cleaning job at the same time, so I had to fully remove my intake manifold anyway. I'm saving this DIY for next time though. Excellent job here in this one. Thanks a lot! There's no reason to pay a dealer hundreds if dollars for replacing two $15 gaskets located in such an easy to reach area.

I have this very same problem right now on my 07 335 with 50k miles. This thread will help me tremendously. Can any comment on how long it took them? Just curious. Thanks.

I have a 335i MT with oil cooler. Took me about 8 hours. Not difficult, just VERY tedious.

1. The oil coooler makes it much more tedious than the post above. Be prepared to spill a bunch of oil when detaching the oil cooler flange from the oil filter housing (13 mm bolt lying between the oil cooler lines, on a flange that is on the bottom of the oil temperature unit).

2. Also, a bit of a struggle with the intercooler removal (to permit draining coolant) because the intercooler has these torx screw with really shallow heads that are difficult not to strip - the screws are very tightly held in the plastic frame supporting the radiator and intercooler. You cannot drain the coolant without removing the intercooler (contrary to post above - there is not enough room to remove the rad drain screw with the intercooler pushed back). Here is a good video on how to remove the intercooler:

3. I found the manifold a real struggle to pull back from block far enough to access the hidden OFH mounting screw - you REALLY have to pull and wiggle it off the block and think that you may break something in the process. I had bugs drop into the block when I pulled it back (had to vacuum them up - it is an area that collects debris).

4. I had to use a universal joint (with 2 extensions) on the lowermost bolt (the one facing the passenger side of the car) with a torx socket, to avoid stripping it. If you strip this bolt, you will never get it out, so be VERY careful with it and use the right tools!!

5. I applied engine shampoo to the OFH and area the night before the repair and hosed off thoroughly - made the whole process MUCH less grimy and messy (highly suggest this).

6. Finally, I cannot beleive how much road gravel (from winter driving) and bugs are caught around the intercooler - be prepared for a lot of rotten fallout!

Rad. drains about 4 litres of coolant (~1 gallon of 50/50). You lose about 500 mls of oil in the process of R&R the housing/oil cooler lines. Never found any torque values of the manifold nuts and bolt - tightented fairly snug with a small 1/4 inch ratchet (did the tightening in 3 stages, going through the entire nut and bolt set in sequences). Re-used the manifold gasket (would have been very hard to replace this because the mainfold is so hard to pull far away from the block). You will need to use a whole can of brake cleaner (to clean the housing once off the car don't use water based cleaner for this because you will trap water in the oil cooler thermostat housing) and you SHOULD replace the cooolant hose o-ring that impedes access to the OFH screw facing the passenger side of the car.

Advise investing in torx screw socket set and torx driver set - you can easily strip torx bolts using regular sockets (contrary to above posts). Not sure if the whole day was worth saving $1000, or not. Hopefully only have to do this one in the life of my car. It is an idiotic design and should have a fail-safe gasket that never needs replacing - the gasket is a joke; flimsy 50 cents worth of silicone rubber and poorly designed - shame on BMW.

I have everything ready to do this. I'll be up early on Saturday morning and hopefully be done by noon. Fingers crossed.

Update: The job took about 6 hours and there was only one hipcup. After wiping the old gasket residue off the block, I noticed some pitting going on. (photo 1) I used steel wool to clean the area as best I could and bought some high temp gasket maker to fill the small voids. (photo 2) You can see the deterioration of the upper left corner of the gasket in the third photo. Block pitting occurred in this area. But everything went back together nicely.

Some other DIYers have had this problem as well. Could it be a northern climate thing? IDK. Thanks to the OP for putting this together.

Special thanks to edrive90 for his assistance. I like to add some instructions to performing this on a E92 335i with Sports package and 6MT.

You should remove the intercooler to get to the radiator drain plug. The intercooler is super easy to remove. Two T-20 or T-25 torx screw on each side. Then pull the quick-clamp from the charge pipes off. When the intercooler falls out, you will see a blue plastic screw on the driver's side. This screw is the radiator drain plug. Unscrew this to drain the radiator fluid.

1. Once you have remove the intake manifold or pushed it aside, there are 3 bolts to remove on the oil filter housing gasket. The bottom bolt is the worst as you MUST remove the coolant-to-radiator hose by removing those two bolts that hold the flange. Once this hose is removed, you have another problem. The stock oil cooler lines will be in the way and they are difficult to remove out.

"Which two bolts hold the flange? Are they the giant bolts (with tork bits) on the top of the unit? What do you do with the stock oil cooler lines?"

2. You will need a long extension, 12-inches 1/4 drive and go in from the passenger side to break the last bolt on the oil filter housing. I did not remove the radiator fan since I was lazy. There is not much wiggle room to work with. If you get frustrated, I highly recommend now to remove the radiator fan.

2.b. To remove the radiator fan, there are 3 things that must be done. Very simple. On the passenger side at the top corner, remove that T-25 torx bolt. At the top of the radiator, unclip all electrical lines from the clips. At the driver's side, there is a big electrical connector. Un-plug that by squeezing it. At the driver's side, there is a plastic mechanism that latches the radiator fan. Just push this latch so it will release and allow you to glide out the radiator fan.

You will then notice the radiator fan is still held down by a rubber grommet to the outlet charge pipe. If you can't break it free, reach down and lubricate the grommet with synthetic grease like I did. Use a flat head screwdriver to push down on it so you can slide the radiator up. Don't worry, you won't break the grommet. It is quite tough. The grommet has a slit that is designed for a screw driver to slide into.

3. Once you have removed this bolt, remove the other oil filter housing bolts.

4. If you have the stock oil cooler, you will need to unscrew a bolt underneath the oil cooler lines. I believe it is a 12mm. The oil cooler flange will fall out of the oil cooler. At this point, you may see some oil drip.

5. The oil filter housing and oil cooler lines should be removed from the car now as 1-piece. You will need to separate it. There are 3 bolts holding the oil cooler thermostat housing unit to the oil filter housing. You should definitely replace the gasket that is in-between. The gasket part number is: 11427525335

6. Re-install the oil cooler lines into the oil filter housing unit. Bolt everything back up to 22Nm or 16.22 ft-lb.

7. Bolt the oil filter housing back up. Remember to also bolt the coolant hose from the engine block to the radiator back up as well. Again, replace that o-ring as well.

8. Re-install the radiator fan that you just pulled out.

Jump back to step 23 at the top.

1. Once you have remove the intake manifold or pushed it aside, there are 3 bolts to remove on the oil filter housing gasket. The bottom bolt is the worst as you MUST remove the coolant-to-radiator hose by removing those two bolts that hold the flange. Once this hose is removed, you have another problem. The stock oil cooler lines will be in the way and they are difficult to remove out.

"Which two bolts hold the flange? Are they the giant bolts (with tork bits) on the top of the unit? What do you do with the stock oil cooler lines?"

Just used this DIY and finished the job in just over 2 hours. THANK YOU, OP, FOR SAVING ME SOME $$$!!!!

I'd highly recommend anyone doing that to buy the coolant to block o-ring and have it on hand for the job. Mine was toast and unfortunately I didn't have the o-ring. Managed to work it in and it is holding without any leaks but the first place I stop tomorrow after work will be the dealership to grab a replacement.

Excellent DIY.

I picked up a set of female torx sockets and I had absolutely no problems on the 3 OFH bolts.

Take your time, prepare yourself, study this DIY repeatedly, take your time again... and you'll be fine. I'm no mechanic and I managed to get this done pretty quickly. Fast enough that I started when the 49er game got going and finished in time to sit and watch the 4th quarter.